This proposal requests funding for an Olympus Fluoview Confocal Laser Scanning Biological Microscope System. The laser scanning technology of the confocal microscope provides the highest sensitivity and resolution for the analysis of cellular and subcellular components and has the distinct advantage of optical sectioning and three-dimensional reconstruction. The requested system is a desk-top user friendly model, which will be readily available to a number of investigators with modest training times, and includes a printer to prepare data for publication. A common focus of the NIH-supported research is the hormonal and neuronal control of cellular function and of intracellular regulatory components. This system will be used for a number of applications using fluorescent techniques. These include: 1) co-localization of specific proteins using double-labeled fluorescent immunocytochemistry, 2) subcellular localization of signal transduction molecules including receptors and transcription factors within a single cell, 3) evaluation and three dimensional reconstruction of the expression of specific proteins in thick tissues such as embryos where optical sectioning provides distinct advantages over physical sectioning and, 4) tracing of nerve cells in the central nervous system and in fetal hypothalamic cells to analyze how normal physiological processes, neurotransmitters and hormones alter their projections. This confocal microscope system will significantly extend and enhance the research projects of NIH- funded investigators at Southern Illinois University at Carbondale. In addition, this system may be used by other investigators on the Southern Illinois University campus as availability permits.